CN112723913B - Preparation and maintenance method and maintenance device for seawater sea sand concrete - Google Patents
Preparation and maintenance method and maintenance device for seawater sea sand concrete Download PDFInfo
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- CN112723913B CN112723913B CN202011606862.0A CN202011606862A CN112723913B CN 112723913 B CN112723913 B CN 112723913B CN 202011606862 A CN202011606862 A CN 202011606862A CN 112723913 B CN112723913 B CN 112723913B
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- C—CHEMISTRY; METALLURGY
- C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
- C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
- C04B40/00—Processes, in general, for influencing or modifying the properties of mortars, concrete or artificial stone compositions, e.g. their setting or hardening ability
- C04B40/02—Selection of the hardening environment
- C04B40/0263—Hardening promoted by a rise in temperature
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B28—WORKING CEMENT, CLAY, OR STONE
- B28B—SHAPING CLAY OR OTHER CERAMIC COMPOSITIONS; SHAPING SLAG; SHAPING MIXTURES CONTAINING CEMENTITIOUS MATERIAL, e.g. PLASTER
- B28B11/00—Apparatus or processes for treating or working the shaped or preshaped articles
- B28B11/24—Apparatus or processes for treating or working the shaped or preshaped articles for curing, setting or hardening
- B28B11/242—Apparatus or processes for treating or working the shaped or preshaped articles for curing, setting or hardening by passing an electric current through wires, rods or reinforcing members incorporated in the article
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B28—WORKING CEMENT, CLAY, OR STONE
- B28B—SHAPING CLAY OR OTHER CERAMIC COMPOSITIONS; SHAPING SLAG; SHAPING MIXTURES CONTAINING CEMENTITIOUS MATERIAL, e.g. PLASTER
- B28B11/00—Apparatus or processes for treating or working the shaped or preshaped articles
- B28B11/24—Apparatus or processes for treating or working the shaped or preshaped articles for curing, setting or hardening
- B28B11/245—Curing concrete articles
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- C—CHEMISTRY; METALLURGY
- C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
- C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
- C04B40/00—Processes, in general, for influencing or modifying the properties of mortars, concrete or artificial stone compositions, e.g. their setting or hardening ability
- C04B40/02—Selection of the hardening environment
- C04B40/0204—Selection of the hardening environment making use of electric or wave energy or particle radiation
- C04B40/0209—Electric, magnetic or electromagnetic fields
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Abstract
A method for preparing and curing seawater sea sand concrete and a curing device thereof. In the process of preparing concrete by using seawater and sea sand in a low-temperature environment, the chloride ions in the seawater and the sea sand are difficult to remove, so that the strength of the prepared concrete is difficult to ensure. According to the invention, a corresponding power supply power range is estimated according to the heat dissipation efficiency and the current thermal efficiency of the matrix, the assembled curing device is heated according to the estimated power supply power range, the prepared conductive seawater sea sand concrete is injected into the curing device, after the curing device is electrified, the free chloride ions of the concrete are removed by using current, and the self-body heat curing process is realized through the ohmic thermal effect of the conductive seawater sea sand concrete; the plurality of templates comprise a bottom plate and a plurality of side templates, the bottom plate is horizontally arranged, the plurality of side templates are vertically arranged on the bottom plate, two adjacent side templates are detachably connected, and the bottom plate and the plurality of side templates form a containing space matched with conductive seawater and sea sand concrete. The method is used for preparing the seawater sea sand concrete.
Description
The technical field is as follows:
the invention particularly relates to a preparation and maintenance method of concrete and a maintenance device thereof, belonging to the technical field of civil engineering.
The background art comprises the following steps:
in the construction process in cold regions and in the ultralow temperature environment of polar regions, the biggest problem faced by concrete is the problem of frost damage of the concrete. Cracks can occur when the curing is improper, the strength is not developed enough, the durable quality is reduced, and the like. In order to prevent the concrete from being frozen, the construction regulation of the construction engineering in winter defines the freezing critical strength as an important index of the concrete in winter construction, and is used for judging whether the concrete has the capability of resisting freezing. The construction method under the negative temperature condition has a plurality of methods, mainly comprising a heat storage method, a comprehensive heat storage method, an external heating construction method (a steam curing method and a greenhouse method), an antifreeze agent doping method and the like. The heat storage method and the comprehensive heat storage method can obtain better effects when the construction temperature is higher than minus 10 ℃, but in severe cold regions of polar regions, the temperature is often far lower than minus 10 ℃ in winter, even as low as minus 50 ℃, the heat transfer between the concrete and the outside air is quicker in the environment, and the expected effects are difficult to obtain by the methods; there are various heat sources for constructing the external heating method, and a greenhouse method and steam heating maintenance are common. The method has good effect, but for large-scale structural members, such as large-scale projects like hydraulic engineering, road engineering, culvert tunnels, bridges and building structures, the method is inconvenient to implement and needs high cost, labor and a large amount of materials, and the cost is huge. In addition, fresh water resources meeting engineering requirements are lacked in cold regions and polar regions, if seawater is used for preparing concrete, the high content of chloride ions contained in the seawater in the concrete can destroy the chemical corrosion resistance of the concrete, the abrasion resistance of the concrete is directly affected, the strength of the concrete is further reduced, the problems of looseness and insufficient bearing are caused in a concrete structure, the service life of the concrete in the engineering is shortened, the concrete enters a failure state in advance, and at present, methods for reducing the content of chloride ions in the concrete in the cold regions and the polar regions in the ultralow temperature environment are few and few.
In a word, in the construction in the cold area ultralow temperature environment, the concrete curing measures have large energy consumption and potential safety hazards, the content of chloride ions in seawater concrete is difficult to reduce, and the existing curing measures are difficult to match with the preparation and construction of the seawater concrete in the cold area ultralow temperature environment, so that the seawater concrete is difficult to apply to practical engineering after preparation and curing.
The invention content is as follows:
in order to solve the problems mentioned in the background art, the invention aims to provide a preparation and maintenance method of seawater sea sand concrete and a maintenance device thereof.
A preparation and maintenance method of seawater sea sand concrete comprises the steps of predicting a corresponding power supply power range according to heat dissipation efficiency and current thermal efficiency of a base body, heating an assembled maintenance device according to the predicted power supply power range, injecting prepared conductive seawater sea sand concrete into the maintenance device, removing free chloride ions of concrete by using current after the maintenance device is powered on, and realizing self-heat maintenance through ohmic thermal effect of the conductive seawater sea sand concrete.
As a preferable scheme: the process of estimating the corresponding power supply power range according to the heat dissipation efficiency and the current heat efficiency of the substrate is as follows:
the heat release of conductive seawater sea sand concrete test piece includes two parts: one part is heat convection, and heat convection includes heat conduction and heat convection dual mode again, and the exothermic another part of conductive sea water sea sand concrete test piece is then radiation heat dissipation, and the circular telegram is crossed the back to conductive sea water sea sand concrete test piece, in the stage of maintenance temperature rapid rising, conductive sea water sea sand concrete test piece themogenesis will be greater than exothermic, and this difference increases earlier the back and reduces, and the formula that arouses the temperature difference between test piece of high temperature and the microthermal outdoor environment is:
Q G -Q R ＝Cm△T>0 (1)
in the above formula Q G -the heat absorbed by the test piece;
Q R -the heat given off by the test piece;
c is the specific heat of the test piece;
delta T is the temperature change value of the test piece;
along with the continuous progress of ohmic heating maintenance process, the self temperature of electrically conductive sea water sea sand concrete test piece will also rise constantly, and finally electrically conductive sea water sea sand concrete test piece heat absorption reaches the equilibrium state with exothermic, and the maintenance temperature of electrically conductive sea water sea sand concrete test piece will also no longer change this moment, and this temperature is exactly the final maintenance temperature of structure under the ohmic heating maintenance condition, and the formula of final maintenance temperature is:
Q G -Q R ＝Cm△T＝0 (2)
when the heat absorption capacity and the heat release capacity of the conductive seawater sea sand concrete test piece reach a balance state, the heat absorption power and the heat release power of the conductive seawater sea sand concrete test piece also reach a balance, and the balance relation between the heat absorption and release power and the final curing temperature of the conductive seawater sea sand concrete test piece realizes a curing temperature behavior controllable process;
in the above process, the formula of the thermal power when the heat convection part dissipates heat is as follows:
P＝hA(T-T t ) (3)
in the formula, P represents the heat dissipation power of the structure for heat convection;
h-coefficient of thermal conductivity; the thermal conductivity is a physical quantity related to the material property of the test piece and the physical parameters of the surrounding fluid;
a is the area of the heat dissipation surface of the test piece, and the area value can be obtained according to the structure size;
t-temperature of the structure itself;
T t -the temperature of the environment in which the structure is located;
it is worth to be noted that the heat conductivity h is a physical quantity related to the material property of the test piece and the physical property parameters of surrounding fluid, and the heat conductivity of the electric conduction type seawater sea sand concrete test piece is measured by adopting a hot plate method in the actual engineering;
the formula of the radiation heat dissipation power of the conductive seawater sea sand concrete test piece is as follows:
P＝σ·ε·A·(T 4 -T t 4 ) (4)
σ in the above equation-the radiation constant of the black body, which is a fixed value;
epsilon-blackness, epsilon =0.94;
thereby obtain the power balance when the heat absorption and discharge power of electrically conductive sea water sea sand concrete test piece self reaches the balance and reaches the maximum maintenance temperature promptly, the power balance formula is:
P＝h·A·(T-T t )+σ·ε·A·(T 4 -T t 4 ) (5)
therefore, under the ohmic heat curing condition, the relationship between the electric power applied to the structure and the final curing temperature of the structure has a corresponding functional relationship, and the electric power applied to the structure can be controlled according to the required curing temperature.
As a preferable scheme: the assembly process of the curing device is as follows: maintenance device includes a plurality of templates, when the template is the steel form, the maintenance device cooperation is provided with induction heating system, induction heating system includes the temperature controller, a plurality of ion concentration sensor and a plurality of first temperature sensor, a plurality of template equipment form the box, the top of box is the opening end, the inner wall of every template is provided with ion concentration sensor, the inside first temperature sensor that is provided with of box, first temperature sensor cooperation is provided with the temperature controller, the template circular telegram forms the electrode template, a plurality of electrode templates constitute with electrically conductive formula sea water sea sand concrete matched with circular telegram return circuit.
As a preferable scheme: stirring the conductive phase and the cementing material for 10 minutes to be uniform, then adding mixed liquid of the admixture and seawater, continuously stirring for 5 minutes, then adding the aggregate, stirring the aggregate, the cementing material and the conductive phase together to form the conductive seawater sea sand concrete, and ensuring that the fluidity index of the conductive seawater sea sand concrete reaches 120-160 mm, wherein the conductive phase is a conductive phase except for a steel bar, and is carbon fiber, carbon nanofiber, graphene, carbon nanotube, steel fiber or carbon black.
As a preferable scheme: the temperature controller controls the temperature threshold value of the first temperature sensor in the box body to be in a range of 70-90 ℃, and when the temperature is lower than 70 ℃, the temperature controller is started to heat the conductive seawater and sea sand concrete.
As a preferable scheme: the induction heating system further comprises a plurality of second temperature sensors, the second temperature sensors are arranged on the inner wall of each template in a matched mode, the temperature controller controls the value range of the temperature threshold value of the second temperature sensor located in the box body to be 40-60 ℃, when the temperature is lower than 40 ℃, the temperature controller is started to heat the conductive seawater sea sand concrete, and when the temperature exceeds 60 ℃, the temperature controller is closed.
The curing device used in the preparation and curing method of seawater sea sand concrete comprises a plurality of templates, wherein the templates comprise a bottom plate and a plurality of side templates, the bottom plate is horizontally arranged, the side templates are vertically arranged on the bottom plate, the adjacent two side templates are detachably connected, and the bottom plate and the side templates are formed with accommodating spaces for accommodating the conductive seawater sea sand concrete.
As a preferable scheme: the outer wall of each side template is provided with a groove, a plurality of square seat bodies are arranged in the grooves, a moving channel is formed between the square seat bodies, a plurality of electric conductors are arranged in the moving channel in a sliding fit mode, and the two electric conductors in the adjacent side templates are connected through electrified flat wires.
As a preferable scheme: an insulating strip is arranged between two adjacent side templates which are connected through an electrified flat wire.
As a preferable scheme: the template is a steel template or a wood template.
Compared with the prior art, the invention has the following beneficial effects:
1. the invention relates to a method and a device for preparing and curing seawater high-performance concrete under an ultralow temperature condition, which are suitable for field construction in a severe cold environment in polar regions, shorten the conventional 28-day concrete curing period to two days, simultaneously can also utilize sea sand to prepare conductive seawater sea sand concrete nearby, realize continuous and energy-saving curing of the conductive seawater sea sand concrete through a curing device, and realize a comprehensive dechlorination effect in the curing process.
2. The curing process of the invention does not need manual supervision throughout the process, the curing mode has the characteristics of reciprocating circulation, safety and energy saving, the chloride ion concentration in the structural member can be tested in situ, the cured concrete is always in an effective temperature range in the whole curing process, the defect of inconsistent curing effect caused by ineffective low temperature or high temperature is avoided, the uniform curing of each position of the concrete is ensured, and the high-quality compressive strength of the cured concrete in the extremely low temperature environment is ensured.
3. The maintenance method disclosed by the invention is low in raw material cost, the conductive phase is carbon fiber, carbon nanofiber, graphene, carbon nanotube, steel fiber or carbon black, the conductive phase is good in conductive effect and thermal property, and the conductive phase can heat the concrete for a long time in an ohmic thermal effect mode. The temperature setting threshold of the temperature controller is also suitable for early maintenance of concrete, and the C-S-H gel generated by hydration reaction can not be thermally decomposed due to overhigh temperature on the basis of ensuring the maintenance temperature. The adding process of the conductive phase in the preparation process is simple, and the method is suitable for construction sites.
4. In the preparation process, the volcanic ash material with high activity is added, so that the hydration reaction is more sufficient, more hydration products are generated, more chloride ions are fixed in a physical combination and chemical combination mode, and the content of the chloride ions in the structure is ensured to be in a safe range.
5. The maintenance device can realize the dynamic dechlorination process and the static dechlorination process which are carried out in stages, and the dechlorination effect is stable, reliable and comprehensive.
6. The maintenance device is simple, low in cost, comprehensive and uniform in maintenance effect, free of complex mechanical structure, easy to machine and move and capable of being repeatedly used.
7. According to the invention, the preliminary test proves that the method is suitable for the environment with extremely low temperature, and is particularly suitable for cold area hydraulic engineering, road engineering, culvert tunnels, bridges and building structures. The invention can prolong the construction days in cold regions, has more uniform and obvious concrete curing effect in low-temperature construction, and ensures the construction quality.
Description of the drawings:
for ease of illustration, the invention is described in detail by the following detailed description and the accompanying drawings.
Fig. 1 is a schematic view of a first three-dimensional structure of the maintenance device of the present invention, wherein the arrow direction is the pouring direction of the conductive seawater sea sand concrete;
FIG. 2 is a schematic diagram of the front view structure of the template;
FIG. 3 is a schematic view of a top view of the maintenance device, in which the double-headed arrows indicate the direction of current flow;
FIG. 4 is a second perspective view of the curing device of the present invention;
FIG. 5 is a bar graph of the flexural strength of the seawater sea sand concrete prepared and cured according to the present invention;
FIG. 6 is a bar graph of the compressive strength of the cured seawater sea sand concrete prepared according to the present invention;
fig. 7 is a block flow diagram of an induction heating system.
In the figure, 1-template; 1-1-sideform; 2-1-ion concentration sensor; 2-2-a first temperature sensor; 2-3-temperature controller; 2-4-a second temperature sensor; 3-groove; 4-a square seat body; 4-1-square plate; 4-2-support column; 5-moving the channel; 6-an electrical conductor; 6-1-round piece; 6-2-locating posts; 7-electrified flat wire; 8-an insulating strip; 9-a square frame; 11-longitudinal stress ribs; 12-stirrup.
The specific implementation mode is as follows:
in order that the objects, aspects and advantages of the invention will become more apparent, the invention will be described by way of example only, and in connection with the accompanying drawings. It is to be understood that this description is made only by way of example and not as a limitation on the scope of the invention. Moreover, in the following description, descriptions of well-known structures and techniques are omitted so as to not unnecessarily obscure the concepts of the present invention.
It should be noted that, in order to avoid obscuring the present invention with unnecessary details, only the structures and/or processing steps closely related to the solution according to the present invention are shown in the drawings, and other details not so related to the present invention are omitted.
The first embodiment is as follows: as shown in fig. 1, fig. 2, fig. 3, fig. 4, fig. 5, fig. 6 and fig. 7, the following technical solutions are adopted in the present embodiment, and the preparation and maintenance method in the present embodiment is to estimate a corresponding power supply power range according to the heat dissipation efficiency and the current heat efficiency of the base body, heat the assembled maintenance device according to the estimated power supply power range, inject the prepared conductive seawater sea sand concrete into the maintenance device, remove free chloride ions of the concrete by using current after the maintenance device is powered on, and implement the self-thermal maintenance process through the ohmic thermal effect of the conductive seawater sea sand concrete.
The second embodiment is as follows: the embodiment is described with reference to fig. 1, fig. 2 and fig. 3, the maintenance device in the embodiment includes a plurality of formworks 1, the plurality of formworks 1 include a bottom plate and a plurality of side formworks 1-1, the bottom plate is horizontally arranged, the bottom plate is a rectangular plate body, the number of the plurality of side formworks 1-1 is four, the four side formworks 1-1 are respectively vertically arranged at four edges of the top surface of the bottom plate, two adjacent side formworks 1-1 are detachably connected, the four side formworks 1-1 are enclosed to form a square frame 9, the square frame 9 is matched with the bottom plate to form an accommodating space matched with conductive seawater sea sand concrete, and the accommodating space is used for injecting the conductive seawater sea sand concrete.
The curing principle of the curing device in the embodiment is an electrified dechlorination curing principle, concrete can be prepared by sea sand, the mixed liquid of the conductive material, the cementing material, the additive and water is added and continuously stirred until the mixed item has good fluidity, and finally, aggregate is added and stirred to form the conductive sea water sea sand concrete. The seawater sea sand concrete with the conductive performance is formed, and the conductive seawater sea sand concrete is electrified while the concrete is maintained, so that the aim of thoroughly and comprehensively removing chloride ions is fulfilled.
The conductive material in this embodiment is other conventional conductive material except for the reinforcing steel bar.
The structure and connection relationships that are not mentioned in this embodiment are the same as those in the first embodiment.
The third concrete implementation mode: the embodiment is further limited by the first or second embodiment, in the embodiment, a groove 3 is processed on the outer wall of each side template 1-1, the groove 3 is arranged along the thickness direction of the side template 1-1, a plurality of square seat bodies 4 are arranged in the groove 3, a moving channel 5 is formed between the square seat bodies 4, a plurality of electric conductors 6 are arranged in the moving channel 5 in a sliding fit manner, and the two electric conductors 6 positioned on the adjacent side templates 1-1 are connected through an electrified flat wire 7.
The square seat body 4 comprises a square plate 4-1 and a support column 4-2 in the embodiment, the plate direction of the square plate 4-1 is the same as that of the side plate 1-1, one side face, facing the groove bottom of the groove 3, of the square plate 4-1 is fixedly connected with the groove bottom of the groove 3 through the support column 4-2, one end of the support column 4-2 is fixedly connected with the groove bottom of the groove 3, the other end of the support column 4-2 is hinged with the square plate 4-1, a gap is formed between every two adjacent square plates 4-1, and the gap formed between the two square plates is a moving channel matched with the electric conductor 6.
Further, the electric conductor 6 comprises a circular sheet 6-1 and a positioning column 6-2, the circular sheet 6-1 is arranged in the groove 3, the circular sheet 6-1 moves along the opening direction of the moving channel 5, the positioning column 6-2 is arranged along the axial direction of the circular sheet 6-1, one end of the positioning column 6-2 is fixedly connected to the center of the circular sheet 6-1, a gap between two adjacent square plates 4-1 is arranged to be matched with the outer diameter of the positioning column 6-2, and the distance between two adjacent supporting columns 4-2 is arranged to be matched with the outer diameter of the circular sheet 6-1.
Furthermore, the circular sheet 6-1 is a metal circular sheet, the positioning column 6-2 is a metal cylinder, after the circular sheet 6-1 is electrified, the circular sheet 6-1 is an electrified circular sheet, and due to the fact that the electric conductors 6 are in sliding fit with the moving channel 5, namely, each electric conductor 6 can move according to the position of the side template 1-1, which needs to be heated or electrified, the moving is rapid, and the operation process is simple.
Furthermore, the shape of the groove 3 is matched with the shape of the side template 1-1, and when the groove 3 is a square groove body, the square seat bodies 4 are arranged in the groove 3 in a square array.
Furthermore, the electrified flat wire 7 is formed by wrapping a flat jacket outside a metal conducting wire, and two positioning columns 6-2 of the adjacent side templates 1-1 are connected through the electrified flat wire 7.
The fourth concrete implementation mode: the present embodiment is further limited to the first, second or third embodiment, and an insulating strip 8 is disposed between the two adjacent sideforms 1-1 connected by the electrified flat wire 7.
The fifth concrete implementation mode is as follows: the embodiment is further limited by the first, second, third or fourth embodiment, when the formwork 1 is a wood formwork, the bottom plate and the plurality of side formworks 1-1 are both wood formworks, and the wood formwork is matched with the grooves 3, the electric conductors 6 and the electrified flat wires 7 to realize a multi-stage dechlorination type maintenance process after the conductive seawater sea sand concrete is prepared.
In this embodiment, the multi-stage dechlorination maintenance process is divided into a dynamic dechlorination stage and a static dechlorination stage, as shown in fig. 3, after the preparation of the conductive seawater sea sand concrete, a conductor 6 is selected from each of the two adjacent side templates 1-1 before the open end of the maintenance device, the selected conductor 6 is a conductor close to the open end of the maintenance device and is a preferred object, the two conductors 6 of the two adjacent side templates 1-1 are connected through a charged flat wire 7, when the four side templates 1-1 are provided, two adjacent side templates 1-1 are correspondingly matched with each other to form two charged flat wires 7, an exposed surface is processed in the middle of each charged flat wire 7 and used for exposing an internal charged conductor to form a charged exposed surface, so as to be conveniently contacted with the conductive seawater sand concrete, after the conductors 6 are electrified, one charged flat wire 7 of the two charged flat wires 7 is a positive flat wire, one charged flat wire 7 of the two charged flat wires 7 is a negative flat wire, a voltage difference between the positive and the negative voltage of the conductive seawater sand concrete is formed between the positive flat wires and the conductive sea sand concrete. The conductive seawater sea sand concrete is poured down through the vertical dechlorination treatment port, the concrete structure is guaranteed to be poured within 5 hours from the departure according to the site construction requirement, in order to prevent the concrete from generating a cold joint, the two times of concrete pouring time is not more than 1.5 hours, and a vibrating rod is used for uninterruptedly stirring at the joint.
As shown in fig. 3, in the process of pouring the conductive seawater sea sand concrete, a current is generated in the direction of a double-arrow between the positive flat wire and the negative flat wire, and the current passes through the flowing concrete to achieve the effect of removing chloride ions, so that the effect of dynamically removing chlorine is achieved in the process of injecting the conductive seawater sea sand concrete, and the electrifying type of the dynamic chlorine removal is direct current.
After pouring into electrically conductive formula sea water sea sand concrete and the accommodation space that curing means formed, curing means cooperation is provided with induction heating system, shows through the control of 2-3 between a plurality of ion concentration sensor 2-1, a plurality of first temperature sensor 2-2 and a plurality of second temperature sensor 2-4 of arranging in advance in accommodation space and carries out circular telegram dechlorination process to the static sea water sea sand concrete that is in the accommodation space, and the dechlorination effect is comprehensive and diversified, strengthens realizing static dechlorination effect to the sea water sea sand concrete in the static maintenance process. The electrification type of the static dechlorination is alternating current.
Dynamic dechlorination process and static dechlorination process cooperate among the curing means can realize the dechlorination process of different stages to electrically conductive formula sea water sea sand concrete among this embodiment, and the dechlorination effect is comprehensive and thorough.
Further, when the conductive seawater sea sand concrete is in a static dechlorination stage, resistance wires are arranged in the electric conductors 6, the electric conductors 6 are attached to the outer walls of the side templates 1-1 at the moment, the arrangement position of each electric conductor 6 can be flexibly adjusted according to actual maintenance conditions, and heat is transferred to the end corners, the center or other positions of the outer side wall of the conductive seawater sea sand concrete through the wood template in a heat transfer mode. Thereby avoiding the problems that the corners of the conductive seawater sea sand concrete which is integrally electrified, heated and maintained are frozen or the strength is insufficient.
In the embodiment, two ends of the dechlorination treatment port between the anode flat wire and the cathode flat wire respectively correspond to the joints of the two side templates 1-1, and each joint is provided with an insulating strip 8.
The sixth specific implementation mode is as follows: the embodiment is further limited by the first, second, third, fourth or fifth embodiment, when the formwork 1 is a metal formwork, the bottom plate and the plurality of side formworks 1-1 are all metal formworks, and the metal formwork is matched with the grooves 3, the electric conductors 6 and the electrified flat wires 7 to realize a multi-stage dechlorination type maintenance process after the conductive seawater sea sand concrete is prepared.
In this embodiment, the multi-stage dechlorination curing process is divided into a dynamic dechlorination stage and a static dechlorination stage, as shown in fig. 3, when the conductive seawater sea sand concrete is prepared and injected into the front of the open end of the curing device, one electric conductor 6 is selected from each of the two adjacent side templates 1-1, the selected electric conductor 6 is the electric conductor close to the open end of the curing device and is a preferred object, the two electric conductors 6 of the two adjacent side templates 1-1 are connected through one electrified flat wire 7, when the four side templates 1-1 are provided, two electrified flat wires 7 are correspondingly matched with each other in pairs of adjacent side templates 1-1, an exposed surface is processed in the middle of each electrified flat wire 7 and used for exposing an internal electrified conducting wire to form an electrified exposed surface, so as to be conveniently contacted with the conductive seawater sand concrete, after the electric conductors 6 are electrified, one electrified flat wire 7 of the two electrified flat wires 7 is an anode flat wire, one electrified flat wire 7 of the two electrified flat wires 7 is a cathode flat wire, the conductive sea sand concrete is formed between the anode flat wire and the seawater sand concrete is dynamically injected into the seawater sand concrete at the cathode flat wire and the seawater sand concrete, thereby realizing the dechlorination stage. The type of current for dynamic dechlorination is direct current.
After pouring into electrically conductive formula sea water sea sand concrete and the accommodation space that curing means formed, curing means realizes static heating effect through the induction heating system that the cooperation set up on the one hand, specifically for through arranging in advance between a plurality of ion concentration sensor 2-1 in the accommodation space, the control demonstration through temperature controller 2-3 between a plurality of first temperature sensor 2-2 and a plurality of second temperature sensor 2-4 carries out circular telegram dechlorination process to the static sea water sea sand concrete that is in the accommodation space, the dechlorination effect is comprehensive and diversified, strengthen the sea water sea sand concrete realization static dechlorination effect to in the static maintenance process. On the other hand, the electric conductors 6 at the two oppositely arranged formworks 1 are electrified, so that the two oppositely arranged formworks 1 form a positive-level formwork and a negative-level formwork, the alternating current provides electric power for the metal formworks, and the two metal formworks are electrified to realize static dechlorination treatment on the conductive seawater sea sand concrete clamped between the two.
Dynamic dechlorination process and static dechlorination process cooperate among the curing means can realize the dechlorination process of different stages to electrically conductive formula sea water sea sand concrete among this embodiment, and the dechlorination effect is comprehensive and thorough.
In the embodiment, an insulating strip 8 is arranged at the joint of two adjacent side templates 1-1.
Further, the template 1 is a steel template.
The seventh embodiment: this embodiment is the further limited of embodiment one, two, three, four, five or six, and every recess 3 department corresponds the cooperation and is provided with a square cover plate, and square hole has been processed on the square cover plate, and a plurality of square pedestal 4 sets up in square hole.
The specific implementation mode is eight: the present embodiment is further limited to the first, second, third, fourth, fifth, sixth, or seventh embodiments, and the process of estimating the corresponding power supply range according to the heat dissipation efficiency and the current thermal efficiency of the substrate in the present embodiment is as follows:
for the concrete test piece cured by ohmic heat, the ohmic heat generated by constant power electrification is the main heat source for the test piece to generate heat, so that only the heat brought by the ohmic heat is discussed when the test piece generates heat. The heat release of the test piece mainly comprises two parts, one part is convection heat transfer, and the convection heat transfer comprises the basic heat transfer mode of two parts of heat conduction and convection heat transfer. In general, convective heat transfer can be further divided into turbulent flow and laminar flow depending on the flow conditions. The other part of the test piece heat release is radiation heat dissipation, and an object above absolute zero (-273 ℃) can constantly change heat energy into radiation energy, namely constantly and outwards dissipate the heat in a radiation heat dissipation mode. And the higher the temperature, the greater the total energy radiated.
After the test piece is electrified, in the stage of rapid rise of the curing temperature, the heat generation of the test piece is larger than the heat release, and the difference is increased and then reduced, which causes the temperature difference between the high-temperature test piece and the low-temperature outdoor environment, as shown in formula (1).
Q G -Q R ＝Cm△T>0 (1)
In the formula Q G -the heat absorbed by the test piece;
Q R -the heat given off by the test piece;
c is the specific heat of the test piece;
delta T is the temperature change value of the test piece itself.
With the continuous proceeding of the ohmic heat curing process, the self temperature of the concrete structure will be continuously raised, and finally the heat absorption and the heat release of the test structure will reach a balance. At this time, the curing temperature of the structure will not change, and this temperature is the final curing temperature of the structure under the ohmic heat curing condition, as shown in equation (2).
Q G -Q R ＝Cm△T＝0 (2)
It is worth noting that, since both the heat absorption and heat release are time and power related parameters, when the heat absorption and heat release of the structure itself are balanced, its own heat absorption and heat release power are also balanced. The balance relation between the heat absorption and discharge power and the final curing temperature can be realized, and the behavior of the curing temperature is controllable.
First, the thermal power when the heat is dissipated to the heat transfer part is discussed as shown in equation (3).
P＝hA(T-T) (3)
P is the heat dissipation power of the structure for heat convection;
h-coefficient of thermal conductivity; the thermal conductivity is a physical quantity related to the material property of the test piece and the physical parameters of the surrounding fluid;
a is the area of the heat dissipation surface of the test piece;
t-temperature of the structure itself;
T t -the temperature of the environment in which the structure is located;
next, the heat dissipation power of the radiation heat dissipation is discussed, and the expression of the radiation heat dissipation power is shown in formula (4):
P＝σ·ε·A·(T 4 -T t 4 ) (4)
wherein sigma is the radiation constant of the black body and is a fixed value;
epsilon-blackness, and the blackness of the concrete material is 0.94 by looking up a table.
On the basis of the above series of discussions, the formula of the power balance when the heat absorption and discharge power of the test piece reaches the balance, that is, the maximum curing temperature is reached, can be obtained as shown in (5):
P＝h·A·(T-T t )+σ·ε·A·(T 4 -T t 4 ) (5)
in the formula, h is the concrete heat conductivity coefficient, and according to a specific concrete mixing ratio, the concrete heat conductivity coefficient is measured before use, and A is the area of a cast concrete heat dissipation surface and can be obtained according to actual measurement of a specific structure. In the above formula, e =0.94. In the above formula, h, A and epsilon are parameters related to material properties, so that the relationship between the electric power applied to the structure and the final curing temperature of the structure has a corresponding functional relationship under the ohmic heat curing condition, and the electric power applied to the structure can be controlled according to the required curing temperature.
The specific implementation method nine: the embodiment is further limited by the first, second, third, fourth, fifth, sixth, seventh or eighth specific embodiment, the curing device is cooperatively provided with an induction heating system, the induction heating system comprises a temperature controller 2-3, a plurality of ion concentration sensors 2-1 and a plurality of first temperature sensors 2-2, the plurality of templates 1 are assembled to form a box body, the top end of the box body is an open end, the ion concentration sensors 2-1 are arranged on the inner wall of each template 1, the first temperature sensors 2-2 are arranged in the box body, the temperature controllers 2-3 are cooperatively arranged on the first temperature sensors 2-2, the templates 1 are electrified to form electrode templates, and the plurality of electrode templates form an electrified loop matched with the conductive seawater and seawater sand concrete. During which it is ensured that the position of the sensing system cooperating with the curing device is not deflected.
Further, the temperature controller 2-3 controls the temperature threshold of the first temperature sensor 2-2 in the box body to be 70-90 ℃, the optimal temperature threshold is 70 ℃, and when the temperature is lower than 70 ℃, the temperature controller 2-3 is started to heat the conductive seawater sea sand concrete.
Further, the induction heating system further comprises a plurality of second temperature sensors 2-4, the inner wall of each template 1 is provided with the second temperature sensors 2-4 in a matched mode, the value range of the temperature threshold value of the second temperature sensors 2-4 controlled by the temperature controller 2-3 is 40-60 ℃, when the temperature is lower than 40 ℃, the temperature controller 2-3 is started to heat the conductive seawater sea sand concrete, and when the temperature exceeds 60 ℃, the temperature controller 2-3 is closed.
The specific implementation mode is ten: the embodiment is further limited to the specific embodiment one, two, three, four, five, six, seven, eight or nine, the conductive sea sand concrete is seawater high-strength high-performance concrete, and the specific preparation process for preparing the conductive sea sand concrete is as follows:
mixing the nano conductive filler and the aggregate, quickly stirring until the conductive filler is attached to the aggregate, then dry-mixing and stirring the carbon fiber serving as a macroscopic conductive phase and the cementing material for 5 minutes, uniformly stirring the carbon fiber and the cementing material, adding a water and water reducing agent mixed solution after the stirring time exceeds 10 minutes, quickly stirring for five minutes, adding the aggregate attached with the nano conductive filler on the surface, and quickly stirring the mixture for eight minutes to obtain the fresh slurry. And (3) testing the slump of the fresh concrete slurry, wherein the tested fluidity index is the slump, and when the slump reaches 120-160 mm, the fresh concrete slurry is considered to have good fluidity.
In the embodiment, the conductive phase comprises carbon fibers, carbon nanofibers, steel fibers and graphene, the auxiliary cementing material comprises fly ash, silica fume, metakaolin, limestone powder, plant ash, coal gangue and blast furnace slag, and the aggregate comprises fine sand, quartz sand, sea sand, stones and ordinary geopolymer.
The curing time of the invention was 48 hours.
The concrete implementation mode eleven: the embodiment is described by combining fig. 1, fig. 2, fig. 3, fig. 4, fig. 5, fig. 6 and fig. 7, the embodiment includes a formwork 1, the formwork is a steel formwork, when the number of the plurality of side formworks 1-1 is four, a square frame 9 formed by surrounding the four side formworks 1-1 once is a rectangular frame, the square frame is fixed by tie bolts, one tie bolt is arranged at every 500mm of vertical distance, and a longitudinal stress bar 11 and a stirrup 12 are arranged inside the square frame 9 according to the structural design requirement to form a reinforcement cage.
Furthermore, before concrete is poured, a corresponding induction heating system needs to be arranged inside the combined structure, namely, an internal first temperature sensor 2-2 is arranged at the central position inside the frame body and is connected with the first temperature sensor 2-2 through a lead, and after the frame is closed, a second temperature sensor 2-4 is adhered to the surface position. The positive and negative poles of the output end of the temperature controller 2-3 are respectively connected with a constant power source power supply input end A and an input end B, the constant power source power supply output end A is connected with the lower part of the side template 1-1, and the power supply output end B is connected with the upper part of the side template 1-1 to form a loop. And the first ion concentration receptor 2-1 is respectively stuck on the inner wall of the side template 1-1 along the X direction, the second ion concentration receptor 2-1 is respectively stuck on the inner wall of the side template 1-1 along the Y direction, and is connected with the first ion concentration receptor 2-1 by a lead, and pouring can be carried out after the connection is finished.
Further: a plurality of templates 1 need to have 2-3mm gaps at the combined joint to reserve so that a lead can pass through the templates 1, and the templates 1 have good conductivity. The second temperature sensors 2-4 are required to be arranged according to the specific size of the structural member, at least the second temperature sensors are arranged in the center on the principle that the number of the second temperature sensors is not less than 2 per square meter, and the number of the second temperature sensors arranged in each plane of the structural member is not less than 1. In addition, the temperature controller 2-3 can automatically set a temperature threshold value to control the constant-power supply. The first ion concentration receiver 2-1 and the second ion concentration receiver 2-1 are arranged according to the specific size of the structural member, at least not less than 4 ion concentration receivers are arranged per square meter, and the number of the ion concentration receivers arranged in each plane of the structural member is not less than 1. Other non-mentioned details are the same as in embodiments one, two, three, four, five, six, seven, eight, nine or ten.
The detailed implementation mode is twelve: the embodiment is further limited by the specific embodiment I, II, III, IV, V, VI, VII, VIII, IX, XI or XI, and the bottom of the maintenance device is matched with an electric conductor 6 and an electric flat wire 7 to realize the dynamic process of the conductive seawater sea sand concrete injection and the subsequent static process to realize the dechlorination treatment. The electric conductor 6 and the electrified flat wire 7 are matched with the two electrified flat wires 7 at the top of the maintenance device to realize the dechlorination process in the vertical direction.
The specific implementation mode is thirteen: this embodiment is further limited to the specific embodiments one, two, three, four, five, six, seven, eight, nine, ten, eleven, or twelve, and the mixing ratio needs to be adjusted on the basis of the first experiment in consideration of the structure requiring high strength as the main performance, and water: cement: silica fume: carbon fiber: the aggregate is 0.25:1:0.3:0.03:1.3, the preparation mode of the concrete is still according to the original method, and the embodiment can be applied to large structures in cold regions.
The specific implementation mode is fourteen: this embodiment is further limited to the first, second, third, fourth, fifth, sixth, seventh, eighth, ninth, tenth, eleventh, twelfth or thirteenth embodiment, and the mixing ratio is adjusted on the basis of the first experiment in consideration of the structure requiring high ion permeation resistance as a main property, and the ratio of water: cement: fly ash: carbon fiber: the aggregate is 0.25:0.8:0.2:0.02:1, the preparation method of the concrete is still according to the original method, and the embodiment can be applied to a pier structure in a cold region.
Furthermore, the number of the internal temperature sensors is not less than three according to the specific size of the structural component, and the number of the temperature sensors is determined according to the original requirement and the structural size.
The concrete implementation mode is fifteen: this embodiment is further limited to the first, second, third, fourth, fifth, sixth, seventh, eighth, ninth, tenth, eleventh, twelfth, thirteenth or fourteenth embodiment, and the mixing ratio is adjusted on the basis of the third experiment in consideration of the need to prepare a structural member of high-strength and high-performance concrete using seawater, and the ratio of water: cement: silica fume: metakaolin: aggregate: the carbon fiber is 0.3:1:0.15:0.2:1.35:0.03.
further, 0.5% of carbon nanofibers are doped in the matrix to improve the conductivity and heat generation efficiency of the structure.
The curing method in the present embodiment is as follows:
the method comprises the following steps: and estimating proper power supply according to the heat dissipation efficiency and the current heat efficiency of the substrate.
Step two: the combined maintenance device comprises:
the method comprises the steps of firstly installing longitudinal stress steel bars 11 and stirrups 12 according to structural design requirements, combining a steel reinforcement cage, respectively pasting a first ion concentration sensor and a second ion concentration sensor on the inner wall of a steel formwork, connecting the first ion concentration sensor and the second ion concentration sensor to an ion concentration receiver through leads, further placing a first temperature sensor 2-2 in the center of the steel reinforcement cage, connecting the first temperature sensor and the second ion concentration sensor to a temperature controller 2-3 through leads, combining a plurality of side formworks 1-1 to form a square frame 9, reinforcing the square frame through matching of pull bolts and nuts, finally connecting the output end of the temperature controller 2-3 with a constant power source, connecting the output end of the constant power source with a maintenance device to form a loop, namely completing the arrangement process of mutual matching of the maintenance device and an induction heating system.
Step three: preparing concrete:
firstly, stirring carbon nanofibers and well-graded aggregate until the carbon nanofibers are uniformly dispersed, secondly, stirring the carbon fibers and the cement until the carbon fibers are uniformly dispersed, then adding a mixed liquid of an additive and seawater, continuously stirring until a mixed item has good fluidity, and finally adding a mixture of the carbon nanofibers and the aggregate, stirring until the mixture has good fluidity, and then putting the mixture into a mold.
Step four: pouring concrete and maintaining:
the temperature controller 2-3 controls the temperature threshold of the first temperature sensor 2-2 to be 70 ℃, and when the temperature is lower than 70 ℃, a temperature control switch of the temperature controller 2-3 is turned on to apply an electric field to the structure; the temperature threshold value of the second temperature sensor 2-4 is controlled to be 60 ℃, and when the temperature exceeds 60 ℃, the temperature control switch of the temperature controller 2-3 is closed. Curing is carried out for 48 hours in this manner.
After curing for two days, the curing effect was evaluated by measuring the compressive strength. According to the invention, the results of multiple sample tests show that the concrete curing agent has uniform and stable curing effect on the concrete in winter construction in cold regions, and has guiding significance on the concrete curing work.
The foregoing shows and describes the general principles and broad features of the present invention and advantages thereof. It will be understood by those skilled in the art that the present invention is not limited to the embodiments described above, which are described in the specification and illustrated only to illustrate the principle of the present invention, but that various changes and modifications may be made therein without departing from the spirit and scope of the present invention, which fall within the scope of the invention as claimed. The scope of the invention is defined by the appended claims and equivalents thereof.
Claims (6)
1. A curing device used in a preparation curing method of seawater sea sand concrete is characterized in that: the marine sand concrete formwork comprises a plurality of formworks (1), wherein each formwork (1) comprises a bottom plate and 4 side formworks (1-1), the bottom plate is horizontally arranged, the 4 side formworks (1-1) are vertically arranged on the bottom plate, the two adjacent side formworks (1-1) are detachably connected, and a containing space matched with conductive seawater sand concrete is formed by the bottom plate and the 4 side formworks (1-1); the templates (1) are assembled to form a box body, and the top end of the box body is an open end;
a groove (3) is processed on the outer wall of each side template (1-1), a plurality of square seat bodies (4) are arranged in the groove (3), a moving channel (5) is formed between the square seat bodies (4), and a plurality of electric conductors (6) are arranged in the moving channel (5) in a sliding fit manner;
when the conductive seawater sea sand concrete is prepared and then is injected into the front of the open end of the maintenance device, the electric conductors (6) close to the open end of the maintenance device in the two adjacent side templates (1-1) are respectively selected, and the two electric conductors (6) of the two adjacent side templates (1-1) are connected through an electrified flat wire (7);
an insulating strip (8) is arranged between two adjacent side templates (1-1) which are connected through an electrified flat wire (7);
the middle part of each electrified flat wire (7) is processed with an exposed surface used for exposing an internal electrified conducting wire to form an electrified exposed surface which is convenient to contact with the conductive seawater sea sand concrete, after the electric conductor (6) is electrified, one electrified flat wire of the two electrified flat wires (7) is an anode flat wire, the other electrified flat wire of the two electrified flat wires (7) is a cathode flat wire, a chlorine removal treatment opening matched with the conductive seawater sea sand concrete is formed between the anode flat wire and the cathode flat wire, the injection position of the conductive seawater sea sand concrete is a chlorine removal treatment opening between the anode flat wire and the cathode flat wire, a voltage difference is formed between the anode flat wire and the cathode flat wire, the conductive seawater sea sand concrete is poured vertically to the chlorine removal treatment opening, in the pouring process of the conductive seawater sea sand concrete, a double-arrow direction between the anode flat wire and the cathode flat wire generates current, the current penetrates through the concrete, and the chlorine removal effect is achieved, so that the direct current effect of dynamic chlorine removal is achieved in the pouring process of the conductive seawater sea sand concrete, and the electrifying type of dynamic chlorine removal is achieved;
the maintenance device is provided with an induction heating system in a matching way;
the template (1) is a metal template or a wood template;
when the template (1) is a metal template: after the conductive seawater sea sand concrete is injected into the containing space formed by the maintenance device, on one hand, the maintenance device realizes a static heating effect through a matched induction heating system and performs an electrifying dechlorination process on the static seawater sea sand concrete in the containing space, on the other hand, the maintenance device is electrified through the electric conductors (6) of the two opposite side templates (1-1), so that the opposite side templates (1-1) form an anode template and a cathode template, and alternating current provides electric power for the metal templates, so that the metal templates are electrified to realize the static dechlorination treatment of the clamped conductive seawater sea sand concrete;
when template (1) is the plank sheathing, pour into electrically conductive formula sea water sea sand concrete into to the accommodation space that curing means formed after, curing means cooperation induction heating system carries out circular telegram dechlorination process to the static sea water sea sand concrete that is in the accommodation space, and the circular telegram type of static dechlorination is the alternating current.
2. The curing apparatus used in the method for preparing and curing seawater sea sand concrete as claimed in claim 1, wherein: the induction heating system comprises a temperature controller (2-3), a plurality of ion concentration sensors (2-1) and a plurality of first temperature sensors (2-2), wherein the ion concentration sensors (2-1) are arranged on the inner wall of each template (1), the first temperature sensors (2-2) are arranged in the box body, and the temperature controller (2-3) is arranged on the first temperature sensors (2-2) in a matched mode.
3. The curing apparatus used in the method for preparing and curing seawater sea sand concrete as claimed in claim 2, wherein: the temperature controller (2-3) controls the temperature threshold value of the first temperature sensor (2-2) in the box body to be 70-90 ℃, and when the temperature is lower than 70 ℃, the temperature controller (2-3) is started to heat the conductive seawater and sea sand concrete.
4. The curing apparatus used in the method for preparing and curing seawater sea sand concrete as claimed in claim 3, wherein: the induction heating system further comprises a plurality of second temperature sensors (2-4), the inner wall of each template (1) is provided with the second temperature sensors (2-4) in a matched mode, the temperature controller (2-3) controls the value range of the temperature threshold value of the second temperature sensors (2-4) located in the box body to be 40-60 ℃, when the temperature is lower than 40 ℃, the temperature controller (2-3) is started to heat the conductive seawater and sea sand concrete, and when the temperature exceeds 60 ℃, the temperature controller (2-3) is closed.
5. A preparation and maintenance method of seawater sea sand concrete is characterized by comprising the following steps: the maintenance device of any one of claims 1 to 4 is adopted to carry out the preparation and maintenance of the seawater sea sand concrete, the preparation and maintenance method comprises the steps of estimating a corresponding power supply power range according to the heat dissipation efficiency and the current thermal efficiency of the matrix, heating the assembled maintenance device according to the estimated power supply power range, injecting the prepared conductive seawater sea sand concrete into the maintenance device, removing free chloride ions of the concrete by using current after the maintenance device is electrified, and realizing the self-heat maintenance process by using the ohmic thermal effect of the conductive seawater sea sand concrete;
the process of estimating the corresponding power supply power range according to the heat dissipation efficiency and the current heat efficiency of the substrate is as follows:
the heat release of conductive seawater sea sand concrete test piece includes two parts: one part is the heat convection, and the heat convection includes heat conduction and heat convection dual mode again, and the exothermic another part of electrically conductive formula sea water sea sand concrete test piece is then radiation heat dissipation, and the back is crossed to electrically conductive formula sea water sea sand concrete test piece circular telegram, at the stage that maintenance temperature rises fast, electrically conductive formula sea water sea sand concrete test piece themogenesis will be greater than exothermic, and this difference increases earlier the back and reduces, and the formula that arouses the temperature difference between test piece and the microthermal outdoor environment of high temperature is:
in the above formula Q G -the heat absorbed by the test piece;
Q R -the heat given off by the test piece;
c is the specific heat of the test piece;
along with the continuous progress of ohmic heating maintenance process, the self temperature of electrically conductive sea water sea sand concrete test piece will also rise constantly, and finally electrically conductive sea water sea sand concrete test piece heat absorption reaches the equilibrium state with exothermic, and the maintenance temperature of electrically conductive sea water sea sand concrete test piece will not change this moment again, and this temperature is exactly the final maintenance temperature of structure under the ohmic heating maintenance condition, and the formula of final maintenance temperature is:
when the heat absorption capacity and the heat release capacity of the conductive seawater sea sand concrete test piece reach a balanced state, the heat absorption power and the heat release power of the conductive seawater sea sand concrete test piece also reach balance, and the balance relation between the heat absorption and release power and the final curing temperature of the conductive seawater sea sand concrete test piece realizes a controllable curing temperature behavior process;
in the above process, the formula of the thermal power when the heat convection part dissipates heat is as follows:
P = hA(T−T t ) （3）
in the formula, P represents the heat dissipation power of the structure for heat convection;
h-coefficient of thermal conductivity; the thermal conductivity is a physical quantity related to the material property of the test piece and the physical property parameters of the surrounding fluid;
a, the area of the heat dissipation surface of the test piece can be obtained according to the structure size;
t-temperature of the structure itself;
T t -the temperature of the environment in which the structure is located;
it is worth to be noted that the heat conductivity h is a physical quantity related to the material property of the test piece and the physical property parameters of surrounding fluid, and the heat conductivity of the electric conduction type seawater sea sand concrete test piece is measured by adopting a hot plate method in the actual engineering;
the formula of the radiation heat dissipation power of the conductive seawater sea sand concrete test piece is as follows:
in the above formula
-the radiation constant of the black body, which is a fixed value;
thereby obtain the power balance when the heat absorption and discharge power of electrically conductive sea water sea sand concrete test piece self reaches the balance and reaches the maximum maintenance temperature promptly, the power balance formula is:
therefore, under the ohmic heat curing condition, the relationship between the electric power applied to the structure and the final curing temperature of the structure has a corresponding functional relationship, and the electric power applied to the structure can be controlled according to the required curing temperature.
6. The method for preparing and maintaining the seawater sea sand concrete as claimed in claim 5, wherein the method comprises the following steps: the process for preparing the conductive seawater sea sand concrete comprises the following steps: stirring the conductive phase and the cementing material for 10 minutes to be uniform, then adding a mixed liquid of the admixture and the seawater, continuously stirring for 5 minutes, then adding the aggregate, stirring the aggregate, the cementing material and the conductive phase together to form the conductive seawater sea sand concrete, and ensuring that the fluidity index of the conductive seawater sea sand concrete reaches 120-160 mm, wherein the conductive phase is a conductive phase except for the reinforcing steel bars, and is carbon fiber, carbon nanofiber, graphene, carbon nanotubes, steel fiber or carbon black.
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